Computers which accept commands through operations performed with pointing devices are becoming commonplace. Pointing devices include but are not limited to "mice" and stylus-addressed digitizing tablets which can be used with, for example, a pen-like writing instrument or the user's finger.
One approach to translate data entered with a pointing input device into machine-interpretable codes is a "soft" keyboard. The soft keyboard is typically implemented by using a dialogue box which displays an image of a keyboard and responds to user interaction with that image. Interactions are accomplished using "pointing" devices such as digitizing tables, touch screens, or computer mice. The user may enter characters by pointing to, and "poking", the desired key in the image. Because character selection is explicit with this technique, data entry tends to be highly accurate. In the past, data entry, using prior art soft keyboards, has been a slow process because the user must first locate the desired "key", and then move the pointer to that key. (The soft keyboard does not permit the user to have multiple fingers positioned for future strokes while the current user selection action is being entered, as does a real, physical keyboard.) Thus, prior art soft keyboards are not well suited for applications which require a substantial amount of data entry.
To overcome the above shortcomings of soft keyboards, a modified machine user interface is provided by the above mentioned U.S. Pat. No. 5,479,536, entitled "Stroke Syntax Input Device (the disclosure of which patent is hereby incorporated by reference). The user interface described in this patent is one which the user can interact with naturally; has a display presentation which does not require an excessive amount of space, and is more suitable than the user handwriting in characters as a means of their entry. This modified machine user interface employs trigram data and displays only those characters most likely to be selected next by the user. It formats the presentation of those characters, and interprets the user's pointing device-entered strokes to cause characters to be selected, de-selected or to cause the characters making up the presentation to be changed.
While such a device proved to be a highly efficient way of entering alphanumeric data, it proved to be disconcerting to certain users who preferred to have a display of the full keyboard for character selection and entry.